Exercise-induced asthma

Introduction to exercise-induced asthma Exercise-induced asthma (EIA) is an acute airway stenosis and airway resistance that occurs after severe exercise in patients with increased airway responsiveness. Sports asthma is not uncommon in clinical practice. According to statistics, 50% to 90% of confirmed asthma patients may have exercise-induced asthma; 40% of patients with undiagnosed allergic rhinitis may have exercise-induced asthma. basic knowledge Sickness ratio: 0.05% Susceptible people: no special people Mode of infection: non-infectious Complications: malnutrition acute pulmonary heart disease

Exercise-induced asthma

(1) Causes of the disease

Exercise is the only motivating factor, and allergic rhinitis can also induce exercise-induced asthma.

(two) pathogenesis

The pathogenesis of exercise-induced asthma has not yet been fully elucidated. At present, the following three factors are considered to be involved in the pathogenesis:

1. Heat loss and water loss

During vigorous exercise, a large amount of air passes through the airway in a relatively short period of time. At the same time, the mouth breathing causes the inhaled air to enter the lower respiratory tract without being moistened and warmed by the nasal cavity, thereby causing the bronchial mucosal temperature to decrease and the airway moisture to be lost. The osmotic pressure of the fluid on the surface of the respiratory epithelium is elevated, and physical stimulation such as increased osmotic pressure and decreased airway temperature can induce bronchial smooth muscle spasm.

2. Inflammatory response and inflammatory mediators

Because the nature of asthma is chronic inflammation of the airways, it is considered that exercise-induced asthma is no exception, but the results are not exactly the same as expected, although some experiments have found that eosinophils and mast cells degranulate lightly in BALF after 3 hours of exercise. Degree increased, but other studies have not found that EIA local airway tissue inflammatory cells and histamine, tryptase, leukotriene C4 and other inflammatory mediators have changed, in recent years, the role of LTD4 in the pathogenesis of EIA has gradually been recognized The concentration of LTD4 in BALF was significantly increased in patients with EIA. The administration of LTD4 receptor antagonist 20 min before exercise significantly reduced the extent of bronchospasm and shortened the recovery time.

3. Neural mechanisms

Some studies have found that EIA patients have lower sympathetic response than normal people during exercise; norepinephrine prevention before exercise can significantly reduce the degree of bronchospasm. In addition, the vagus nerve is also involved in the pathogenesis of EIA.

Exercise-induced asthma prevention

Leukotriene receptor antagonists such as Ankelai and Shun Ning, antihistamine H1 receptor antagonists, calcium channel blockers have a certain preventive effect on EIA.

In daily life, according to the needs of the body, appropriate physical exercise should be strengthened, and some medical equipment should be combined to improve their own quality and disease resistance, strengthen physical exercise and improve their physical fitness. They must choose medical exercises, Tai Chi, according to their physical fitness. Five birds and other projects, adhere to exercise, can improve the body's ability to resist disease, the amount of activity with no obvious shortness of breath, rapid heartbeat and excessive fatigue.

Exercise-induced asthma complications Complications malnutrition acute pulmonary heart disease

Exercise asthma is prolonged and recurring, and it is easy to cause great mental and physical pain. As the disease progresses, the oxygen metabolism disorder is aggravated. These children often have short stature, malnutrition, and hunchback, often meeting similar pieces. The state, some patients with more serious conditions, resulting in pessimistic disappointment and self-destructive attitude, patients due to insufficient attention can not be timely and reasonable treatment, and some developed into bronchiectasis, mostly seen in the right middle lobe. Some develop into bronchiectasis, occasionally with mediastinal emphysema or pneumothorax, severe cases of varying degrees of cardiopulmonary dysfunction, and even pulmonary heart disease.

In fact, exercise-induced asthma not only causes damage to the patient's body, but also causes psychological damage to the patient. Many people with exercise-induced asthma will be afraid of exercise and escape from exercise, which will also gradually reduce the body's resistance. Recovery is not beneficial.

Exercise-induced asthma symptoms Common symptoms Breathing dyspnea Chest tightness Breathing wheezing

EIA can occur in any age group, especially in adolescents. Patients usually develop chest tightness, wheezing, coughing, and difficulty breathing after a few minutes of strenuous exercise. The symptoms peak at 5-10 minutes after exercise stops, and relieve themselves within 30 to 60 minutes. Only a few cases may last longer and require medication.

The appearance of EIA symptoms has a certain relationship with the type of exercise. The most common types of sports in EIA are bicycle, running, figure skating, while sports in warm and humid environments, such as swimming, badminton, and tennis, are less likely to appear in EIA. .

EIA can occur in any climatic conditions, but the chances of seizures increase when breathing dry and cold air, but not in warm, humid climates.

EIA should be considered in the presence of typical symptoms during or after exercise, but due to the large differences in the reliability of the medical history, any patient must be sure that exercise-induced asthma diagnosis requires an exercise-stimulating test.

The relevant anti-asthmatic drugs must be discontinued before the exercise stimulation test. Oral drugs, especially the 2 receptor agonists, should be discontinued for at least 24 hours; the aerosol should be discontinued for at least 6 hours.

The standard exercise challenge test, the exercise plate test, subjects continued to exercise for 6 to 8 minutes with maximum heart rate [(220-age) 80%] (sub-maximal heart rate), measured at intervals of 5 minutes before and after exercise. 1 time FEV1 or PEF, lasts until 15 to 30 minutes after the stop of exercise. If FEV1 or PEF drops more than 15% before exercise, it is positive for exercise stimulation test. It can diagnose exercise-induced asthma. The test should guide the test. The mouth is breathing, if necessary, the nose clip is used. If the exercise test is positive, chest tightness, wheezing, difficulty in breathing, etc., and wheezing sound may appear in the lungs. At this time, short-acting 2 receptor agonistic drugs may be given to relieve symptoms. Restoring lung function, severe cardiopulmonary disease or other diseases affecting exercise are contraindicated in exercise stimulation test; middle-aged and elderly people must have ECG monitoring when conducting tests. The whole test procedure should be carried out under the supervision of experienced medical personnel, and appropriate Rescue measures.

If the standard exercise excitation test cannot be performed under the condition limit, the simple outdoor run-up method can be used instead. The subject runs 4-8 min or 1 mile (1 km=0.62 miles) outdoors, before running, 515 after running. PEF was measured at 30 min, and the positive judgment standard was the same as above. This method is suitable for population screening.

Exercise-induced asthma examination

Some experiments have found that the eosinophils and mast cells in the BALF have a slight increase in degranulation after 3 hours of exercise, but other studies have not found EIA local airway tissue inflammatory cells and histamine, tryptase, leukotriene C4 and other inflammatory mediators. The content has changed.

Exercise test :

The standard exercise challenge test, the exercise plate test, continued to exercise for 6-8 hours in the state of maximal heart rate [(220-age) x 80%] (sub-maximal heart rate), 5 min before and after exercise. The FEV1 or PEF was measured once and continued until 15 to 30 minutes after the exercise was stopped. If the FEV1 or PEF decreased more than 15% before exercise after exercise, the exercise stimulation test was positive, and the exercise-induced asthma was diagnosed.

Diagnosis and identification of exercise-induced asthma

Through exercise tests and pulmonary function tests, patients can get accurate diagnosis, but in clinical cases, they are often diagnosed based on symptoms, medical history, and physical examination.

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